Surgical or accidental wounds are typically closed with a length of filament, commonly referred to as a suture, that is introduced into the tissue by a sharp metal needle attached thereto. Sutures are used to make stitches to close the wound by holding the tissues together for healing and re-growth. Sutures are used in a wide variety of procedures, including surgical procedures for wound closure, to close the skin in plastic surgery, to secure damage or severed tendons, muscles or other internal tissues, and in microsurgery on nerves and blood vessels. Generally, the suture needle is used to penetrate and pass through tissue, pulling the suture through behind it. The opposing faces are then approximated together, the needle removed, and the ends of the suture are tied in a knot to secure it in place. The knotting procedure allows the tension on the filament to be adjusted to accommodate the particular tissue being sutured and to control the approximation, occlusion, attachment or other conditions of the tissue. The ability to control tension is extremely important, regardless of the type of surgical procedure being performed.
Suturing and knot-tying are time-consuming parts of most surgical procedures, particularly in microsurgery and endoscopic surgery where there is limited space to manipulate the suture. For adequate closure of some wounds, the suture material must be of a high tensile strength and multiple stitches must be applied. When the tissue structure is weak or when the closure is in a deep layer, the security of the stitch is especially important. For those tissues that are excessively weak, such as friable organs such as the liver or kidney, suturing is virtually impossible with ordinary sutures, as the tension of the suture in these organs is enough to sever the tissue, which is sometimes referred to as the “cheese wire” effect.
Knots that secure sutures in tissue also present problems. For instance, the tissue is distorted when it is secured by the suture under excess tension from the knots. Localized tensions from the knots also contribute to scar formation. The bulk of the knots is also an impediment to wound healing in internal applications, and/or may be detectable or palpable by the patient through the layers of tissue. For permanent sutures, such as those made from polyesters or polypropylenes, the knots remain indefinitely. Even with absorbable sutures, however, the area around the knots can be sensitive, even for an extended period of time after the knots are gone. Consequently, minimizing the knot mass and size, as well as position, is important to the comfort of the patient. Knots are also believed to be a major source of surgical site infection, as they have the potential to hold bacteria during surgical procedures.
Alternatives to conventional sutures for wound closure are known including fasteners (i.e., staples, clips, tacks or the like) and surface adhesives. Fasteners have relatively high strength and save time, but are not as accurate as sutures and are bulky, and may be painful if they must later be removed. They are also generally unsuitable for deeper layers of tissue, and do not provide the advantage of adjustable tension as do sutures. Adhesives have relatively low holding forces and are unsuitable for many applications.
Recently, barbed sutures have been developed in an effort to avoid the time consuming knot tying steps associated with standard suturing. Multiple barbs project outwardly from the suture shaft in a single direction, and are designed to allow passage of the suture in one direction, but to resist movement or slippage in the reverse direction. Such a unidirectional barbed suture will still require knots at one end (the end toward which the barbs face) to keep it secure. Bi-directional barbed sutures have barbs facing in one direction on one end of the suture and barbs facing in the opposite direction on the other side of the suture. Insertion of this type of barbed suture requires a needle at both ends, and requires that the suture be passed through the tissue in two opposing directions, which is more complicated for a surgeon and limits the applications within which it can be used.
Prior use has also been made of looped sutures, in which both ends of the suture loop are secured to a single needle. Although the tensile strength is increased due to the presence of two filaments, looped sutures still require knotting to anchor the ends of the suture, and require that tension be applied to the suture by another person as the surgeon makes successive stitches. Further, these looped sutures are also subject to slippage within the tissue as they are inserted and/or while securing with knots, and also do not overcome the cheese wire effected when used in friable tissue.
Co-pending U.S. application Ser. No. 11/801,414, filed on May 9, 2007, introduced a novel looped, tissue-grasping suture to overcome some of the disadvantages described above. This co-pending application is hereby incorporated by reference in its entirety. As illustrated in FIGS. 1-3 of that application which are reproduced herein, these looped, tissue-grasping devices 10 include a looped suture filament having a first portion 12 and a second portion 14 having first and second ends 16, 18 respectively that are secured to a needle 20. At least a portion of the first and second portions include a plurality of tissue grasping elements or barbs 22 extending outwardly from the suture shaft in a direction away from the needle. These barbs may be of any suitable configuration and formed by any suitable means, and may project in any manner from the respective strands. For example, they may be aligned along the respective strands in any manner, such as aligned opposite one another as shown in FIGS. 1 and 2, or aligned on a single side as shown in FIG. 3. Any other configuration, such as staggered, random, etc., can also be used so long as the tissue grasping elements of both strands face the same direction, away from the suture needle. For the purposes of this disclosure, the terms “barb” and “tissue grasping” will be used interchangeably, in that either term is intended to mean elements that project outwardly from a suture shaft. These elements may be formed by cutting into the suture shaft, or may be formed by press forming, stamping or the like, and the use of one term or the other is not intended to impart structure or material limitations as to the type of projection and/or type of material used.
Multiple configurations and representative methods for use are described in this co-pending application. However, such described devices can be used in methods and procedures not described therein, and which cannot be accomplished with any previously known devices, including previously known barbed sutures or looped sutures alone.